(CNN)Saudi Arabia's fresh public willingness to send ground troops into Syria is drawing ridicule from the kingdom's chief regional rival.

The commander of Iran's revolutionary guard on Saturday mocked Saudi Arabia's declaration that it is prepared to commit ground troops to fight ISIS in war-torn Syria.

"They claim they will send troops (to Syria), but I don't think they will dare do so," Maj. Gen. Ali Jafari told reporters in Tehran, according to Iran's semiofficial Fars news agency. "They have a classic army and history tells us such armies stand no chance in fighting irregular resistance forces."

"This will be like a coup de grace for them. Apparently, they see no other way but this, and if this is the case, then their fate is sealed," Jafari added, according to Fars.

Iran and Saudi Arabia, led by regimes representing opposing Islamic sects, already are bitter rivals. A years-long civil war in Syria has stoked tensions -- Iran is one of the Syrian regime's few allies, while Saudi Arabia has given financial aid and weapons to rebels.

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On Thursday, Saudi Brig. Gen. Ahmad Asiri, a military adviser to the kingdom's defense minster, said that the Saudis are willing to send -- as part of an international coalition -- ground troops into Syria to fight ISIS, the terror group that has captured swaths of territory in Syria during the war there.

And on Friday, two Saudi officials told CNN that the kingdom plans to run in March a multinational military training exercise -- involving as many as 150,000 troops -- to prepare for future anti-ISIS operations.

Most of the personnel will be Saudis; troops from Egypt, Sudan and Jordan have already arrived in the kingdom for the exercise, and troops from other countries -- Morocco, Turkey, Bahrain, the United Arab Emirates and Qatar -- are expected, the officials said.

Jafari's comment came three days after peace talks for the Syrian conflict were put on hold amid anger among Syrian opposition groups over a Russian air campaign over the northern Syrian city of Aleppo. Russia openly joined the civil war in September, backing the forces of Syrian President Bashar al-Assad with airstrikes.